WO2006063647A1

WO2006063647A1 - Gas spring/damper unit

Info

Publication number: WO2006063647A1
Application number: PCT/EP2005/012276
Authority: WO
Inventors: Christof Behmenburg; Heinz Job; Thomas Engelke; Jörg Kock; Hermann Hoinkhaus
Original assignee: Continental Aktiengesellschaft
Priority date: 2004-12-14
Filing date: 2005-11-16
Publication date: 2006-06-22
Also published as: US7886882B2; EP1831580B1; DE102004060002A1; JP4907547B2; EP1831580A1; US20080000739A1; JP2008523328A; KR20070098961A; ATE416332T1; KR101239787B1; DE502005006176D1

Abstract

The invention relates to a gas spring/damper unit (1) comprising at least one movably mounted displacement piston (2) and two displacement chambers (3, 4) whose volume increases or diminishes according to the direction of travel of the displacement piston (2) and which are interconnected via overflow ducts (6, 7) in which throttle valves (16, 16', 16', 17, 17', 17', 17'') are disposed. According to the invention, several throttle valves (16, 16', 16', 17, 17', 17', 17'') having different valve characteristics are positioned so as to be effective in one direction of flow. One throttle valve (17) is designed for damping eigenfrequencies ranging from 1 to 1.5 Hz while another throttle valve (17') is designed for damping eigenfrequencies ranging from 10 to 40 Hz.

Description

Continental Corporation

description

Gas spring-damper unit

The invention relates to a gas spring damper unit with at least one displaceably mounted displacement piston and two displacement chambers whose volume increases or decreases depending on the displacement direction of the displacer and which are connected via overflow, in which throttle valves are arranged.

From DE 43 34 007 A1 a pneumatic spring-damper unit with electromagnetically controllable overflow valves is known, the closing organs are formed by valve spring plates. The magnetic flux flows through the valve spring plates and the valve spring plates interact in their closed position with associated contact surfaces. The closing force is variable by a controllable electromagnet, so that there is a spring-damper unit with variable tuning. With this spring-damper unit, it is possible to set the maximum closing force or preload and to determine from which pressure the valve opens.

From DE 101 35 261 C1, a gas spring-damper unit with overflow throttles is known, which are closed with resilient sealing disks. The resilient sealing discs are not firmly clamped, but determined by a spring force only for a predetermined pressure difference range. After exceeding a certain pressure, the clamping area lifts, wherein the resilient force for loading the sealing disc is preferably applied by a likewise resilient annular disc. Object of the present invention is to provide a gas spring damper unit, which is simple and can be easily adapted to the desired suspension characteristics.

According to the invention this object is achieved by a gas spring damper unit having the features of claim 1, wherein a plurality of throttle valves are arranged with a different valve characteristic in a flow direction effectively, wherein a throttle valve for damping of natural frequencies in the range of 1 to 1, 5 Hz and another throttle valve is designed for damping natural frequencies in the range of 10 to 40 Hz. By combining a plurality of throttle valves in a flow direction with different valve characteristics, that is, with different opening times, flow cross sections and flow resistance, it is possible in a simple manner to assemble a gas spring-damper unit which is optimally adapted to the respective application. Thus, for example, it is possible to provide a relatively high damping even at low damping speeds in order to calm the vehicle body, which has a natural frequency in the range of 1 to 1.5 Hz, for use in vehicles. During normal operation and when higher damper speeds occur, the ratio of damper force and damper speed may be changed to achieve a desired ride. When exceeding a fixed speed or other parameters, another valve, which is responsible, for example, for the damping of the vehicle axle, which has a natural frequency in a range of 10 to 40 Hz, open, and limit the damper force. Thus, it is possible to adjust the damper force characteristic also for large damper speeds, with an adaptation of the body damping on vehicles does not automatically lead to a very steep curve at higher speeds and thus automatically to a no longer adaptable change in the axle damping, ie the attenuation of higher frequencies got to. A further development of the invention provides that the throttle valves, which are effective in each case in a flow direction, open at different flow pressures, ie open the valve bodies, which are under a bias, at different times and release overflow channels. This ensures that only a part of the overflow channels is released up to a certain flow pressure, so that the maximum flow volume remains limited.

In order to provide a different damping characteristic for the tension and compression stage, the throttle valves for the tension and compression stage each have different flow cross sections, in particular the throttle valves for the pressure stage are greater than those for the rebound, to a greater damping in the rebound cause.

A development of the invention provides that the damper system is based on a Vorspannungsadaption, so that the throttle valves are resiliently mounted against the flow pressure and remain closed until a certain flow pressure is reached. The throttle valves thus open only from reaching a certain flow pressure and let the air or gas flow from one displacement chamber into the other. This can be done, for example, that the effective in a common flow direction throttle valves have a different spring preload, while the other geometric dimensions are the same. Alternatively, with the same spring bias and different geometrical dimensions, sequential opening of the various valves can take place in a common flow direction.

A simple way to keep the valves closed under bias is to force the throttle valves into corresponding valve seats via coil springs or axial-expansion coil springs. An advantageous embodiment of the invention provides that the displacement piston is designed as a double-acting displacer, which is displaceably mounted in a cylinder. If the displacer piston is moved in one direction, the volume of the displacer chamber lying in the direction of movement decreases while the volume of the other displacer chamber increases accordingly. As a result, the structural complexity is reduced, since only one cylinder with a piston rod and a piston must be provided. In principle, however, it is also possible to provide two or more cylinders and pistons and to arrange the throttle valves in connecting lines or overflow channels. A particularly compact embodiment of a gas spring-damper unit is obtained when the throttle valves are mounted within the displacer, with the possibility exists to provide the individual valves with valve sets, spring and valve plates or valve body as a structural unit and insert it into the displacer. It is also possible to use modules with several valves with different valve characteristics in the displacement piston, for example, four throttle valve modules, two of which are aligned in the pressure direction and two in the pulling direction.

Some throttle valves only open at a certain adjustment speed. Even with very slow suggestions, it is often desirable to provide low damping forces. To achieve this, at least one bypass is formed between the displacement chambers, which is provided for a passage of a small amount of gas from one displacement chamber into the other displacement chamber. The bypass simulates the friction present in a conventional damper and also allows for level adjustment by increasing or decreasing the total gas flow, thus raising or lowering the level. The bypass can also be formed in a throttle valve or in a module comprising a plurality of throttle valves.

In order to make a separate adjustment of the damper characteristic with respect to the train or compression stage, is a flow direction Bypass formed, which is effective only in this direction. Contrary to this flow direction, the bypass can be closed by a smooth-running flap. In this case, it is provided that the bypass in one flow direction has a larger flow cross section than the bypass in the other flow direction, preferably the bypass will have a larger flow cross section in the pressure direction than in the direction of pull.

A development of the invention provides that at least one adjustment device for adjusting the valve characteristic, in particular the bias voltage of at least one throttle valve, is provided in order to be able to directly influence the throttle system of the gas spring / damper unit. Thus, when installed, the damper characteristics of the gas spring-damper unit can be changed and thus the chassis of a vehicle can be adapted to the requirements under changing environmental conditions. By changing the bias voltage, for example, the damper force limiting valve, the so-called "blow-off valve, the maximum achievable damping force can be increased or decreased.

To simulate the friction in a gas spring-damper unit, as is realized in oil-hydraulic dampers by the bypass valve, another throttle valve is provided, the characteristics, ie the opening time and the opening or opening angle can be changed to a larger or to be able to realize smaller damping in the gas spring damper unit. The change in the valve characteristic is preferably effected by an adjusting device which is associated with the throttle valve or valves.

In one embodiment, the adjusting device has an electromechanical actuator in order to be able to influence the valve characteristic directly and thus to increase the adjustment speed. An adjustment can for example take place in that the valve spring for a throttle valve is associated with a foreign-actuated actuating mechanism via which the Spring preload is changeable. This is done, for example, by an adjusting screw or an adjusting nut, the spring preload is increased or decreased, so that the corresponding valve opens later or earlier.

The second way to adjust the damping, is to vary the size of the inflow surface and thereby change the pressure necessary for opening. Another principle is the control of the amount of air through a slide of a second, parallel throttle unit per flow direction. The parallel choke can also be equipped individually.

An embodiment of the invention will be described in more detail with reference to the accompanying figures.

Show it:

Figure 1 - the basic structure of a gas spring damper unit;

Figure 2 - a damper characteristic curve;

Figure 3 - the basic structure of a coil spring choke;

FIGS. 4a to 4c show components of a damper unit;

Figure 5 - a ring pulley throttle;

Figure 6 - a linear throttle;

Figure 7 - a degressive throttle;

Figure 8 - damper characteristic curves at different valve spring preload;

FIG. 8a - a line of force map;

Figure 9 - a variant of a coil spring choke; and

Figure 10 - a throttle module.

In the figure 1, a gas spring damper unit 1 is shown schematically in sectional view, in which a displaceably mounted displacement piston 2 in a cylinder 20, two displacement chambers 3, 4 is formed. The displacer 2 is acted upon by a piston rod 5 with force, so that a movement can take place in the double arrow direction. If, in the present figure, the displacer piston 2 is pressed down by a force introduction by the piston rod 5, the volume of the displacer chamber 4 decreases as the volume of the displacer chamber 3 increases, minus the displaced volume of the piston rod 5.

Within the displacer 2 overflow channels 6, 7 are formed, which is a passage of the gas in the displacement chambers 3, 4, preferably air, from the one displacement chamber 3, 4 in the each other displacement chamber 4, 3 allow. Throttle valves 16, 17 are arranged in the overflow channels 6, 7, which allow the gas to flow through in each case in one direction and block it in the other.

Also, a bypass 17 '"is formed in the displacement piston 2, through which the gas present in the displacement chambers 3, 4 can flow, so that even with low flow volumes, a certain mobility of the displacement piston 2 is ensured with simultaneous damping.

In order to allow different gas quantities to pass through the bypass 17 '"depending on the direction, a plurality of bypasses can be formed in the displacer 2, which are closed with corresponding flaps, so that a different bypass is activated during a downward movement, the so-called pressure stage, of the displacer 2 as in an upward movement, the so-called rebound.

In order to provide an adapted damper characteristic of the gas spring damper unit 1, the throttle valves 16, 17 are each provided with a different valve characteristic, so that different damper characteristics can be realized for the tension and compression stage. It is also contemplated that those throttle valves 16, 17 operatively disposed in a direction of flow will have different valve characteristics to obtain a finely tuned damper characteristic such that relatively lower damping is provided at lower damper speeds, for example, while at relatively high Damper speeds open other valves that limit the damper force. It is also possible to provide a so-called "blow-off valve that limits the maximum damper force and is designed for high natural frequencies between 10 and 40 Hz.

FIG. 2 shows an exemplary damper force characteristic in which the force F is plotted against the damper speed V. In the diagram, four areas can be seen, in which in the first area I the Force-velocity characteristic is significantly influenced by the bypass 17 '", which has a very small flow cross-section and the two displacement chambers 3, 4 to simulate the friction with each other at slightly greater damper speeds effectively enters a comfort valve, which is essential for the area This comfort valve is, for example, another bypass provided with a biased closure flap and has a larger flow area than the bypass 17 '"on. As the damper speed increases further, a second, preloaded valve is connected for the third region III, the so-called build-up valve, which is preferably designed as a helical spring valve. The build-up valve dampens the vibrations in the range of the structural natural frequencies between 1 and 1.5 Hz, which act predominantly in the vertical direction. By connecting the build-up valve, the slope of the spring force characteristic is reduced. In order to dampen the vibrations, in particular of the vehicle axle, and to limit maximum damper force, a blow-off valve is activated in the fourth section IV, which is effective in the range of natural frequencies between 10 and 40 Hz. The force curve approaches with increasing speed of the envelope H, which represents the damper force F without closed valves, as if all the valve would be located in the maximum open position.

It can be seen from FIG. 2 that the damping force for the rebound stage is plotted above the abscissa and the damping force for the compression stage below the abscissa. It can also be seen from the diagram that the rebound stage and the pressure stage have different damping force characteristic curves, that is to say that the respective throttle valves or bypasses have different valve characteristics or flow cross sections or pretensions. It is provided that the build-up valve is designed as a helical spring valve, which can be easily adjusted by an electric actuator in its bias, so as to directly influence the gas spring throttle unit and the damper force characteristic in the natural frequency of the structure, So change at about 1 to 1.5 Hz. All preloaded valves may be coupled to an actuator that alters the preload according to requirements. By the immediate adjustment of the valves, so in addition to the body valve and the comfort valve and / or the blow-off valve, a very fast adjustment of the damper characteristic can be achieved at a low price. In addition to a screw valve, the blow-off valve can also be designed as a spring disk valve. If the comfort valve is designed as a spring disk valve, this valve can also be integrated in the blow-off valve.

3 shows the basic structure of a valve solution for helical spring throttles, in which the transfer ports 6, 7 are closed within the displacement piston 2 via valve plates 26, 27, which are pressed by coil springs 36, 37 in their valve seats. Depending on the movement of the displacement piston 2, the valve plates 26, 27 are lifted out of the valve seat and moved against the bias of the respective compression spring 36, 37. With larger adjustment speeds V, the pressure and thus the force exerted by the valve plates 26, 27 on the coil springs 36, 37 increases, so that they are compressed and the valve plates 26, 27 are raised. Depending on the configuration of both the cross section of the overflow channels 6, 7, the size of the valve plate 26, 27 and the bias of the coil springs 36, 37 different valve characteristics may be formed differently in a flow direction or for the tension or compression stage.

FIGS. 4a to 4c show an exemplary assembly concept and a gas spring / damper arrangement.

FIG. 4a shows a helical spring valve 16 as a body valve with a valve plate 26, which is held in the valve seat 46 via an axially extending helical spring 36. A bore 56 is closed by a prestressed spring plate and forms the comfort valve 16 ", wherein the bore has a diameter typically between 2 and 6 mm. The exact diameters are determined by the other vehicle parameters. Not shown is the bypass 17 '", which is housed in another valve housing, as well as the blow-off valve 16' is missing, which forms a separate component.

An analogous structure of the respective valves 16, 16 ', 16 ", 17, 17', 17" is shown in Figure 4b, wherein three valves 16, 16 ', 16 "are present for the pressure stage, while the valves 17, 17 ', 17 "are activated for the rebound stage. The blow-off valves 16 ', 17' are designed as separate valves, but may also be integrated in the body valve 16, 17. The valves 16, 16 ', 16 ", 17, 17', 17" for the compression and rebound stages are dimensioned differently depending on the flow direction. The bore 17 '' 'forms a bypass and therewith a fourth throttle valve enabling level control and velvety damping' The bypass 17 '' 'masks friction in a conventional damper and attenuates predominantly small amplitudes such as road surface roughness ,

FIG. 4c shows an arrangement of the blow-off valves 16 ', 17' in a displacer piston or else in a throttle housing 30, which can be inserted into a displacer piston. Similarly, the build-up valves 16, 17 may be installed in the throttle body 30. The valves 16, 16 ', 16 ", 17, 17', 17" are mounted in the throttle body 30 and thus form a preparable unit which can be accommodated in a displacer piston in a fully coordinated manner.

In the figure 5, an alternative throttle principle is shown, in which over annular disks 50 made of spring steel overflow 6, 7 are closed. The annular discs 50 made of spring steel are brought under pretension and depending on the direction of flow of the air or the gas flow, the inner or outer bearing sides open. The advantage of this arrangement lies in its simple structure. The problem is that the rebound and compression can not be set independently. In the figure 6, the principle of a linear throttle is shown, which consists of a perforated throttle body 61, are incorporated in the overflow 6. The openings of the overflow 6 are closed on the tension and pressure side by means of spring washers 60, 67. The bias of the spring washers 60, 67 is exerted by the coil springs 66, 68, alternatively star springs can be used.

FIG. 7 shows a degressive throttle with a throttle body 71, in which overflow channels 6, 7 are formed. The overflow channels 6, 7 are closed in the tension and in the compression direction by spring washers 76, 77, the spring washers 76, 77 have an adjustable, preferably mutually different bias.

All of the spring systems or throttle valve systems of FIGS. 3-7 can be used alternatively or in combination to provide a gas spring damper unit 1.

In the figures 8 and 8a examples of Dämpfkraftkennfelder or Dämpfkraftkennlinien are shown, in which the throttle valves are subjected to a ver¬ changeable bias, so that the adaptation of the damper force characteristic and thus the suspension behavior, such as a vehicle, can be performed. Also in the figures 8 and 8a, the rebound above the abscissa and below the abscissa the pressure level is plotted, whereby here the damper force F is plotted against the damper speed V. In FIG. 8, the adjustment range achievable by means of a bias voltage change is shown in principle, wherein the advantages of the bias control can be seen in the fact that the damping force characteristic curve can also be adapted for high damper speeds. An adaptation of the body damping does not automatically lead to a very stiff characteristic at higher speeds, but at low speeds, a stiff characteristic can be realized, the increase of the damper speed V can be changed. Because the adjustment of the bias voltage acts directly on the throttle, for example, in which an electrome- If a mechanical actuator moves a set screw or an adjusting nut over which the preload is changed, the adjustment is fast.

In the figure 8a damper force characteristics are shown, which are different for the tensile and compressive stage and can be obtained by an adjustment of the body valve 16, 17. In this case, the bias of the valves or of the valve is varied directly, for example by an electric motor or by a change in the setting of a solenoid valve, so that an electric variable throttle is provided for a gas spring damper. This makes it possible, very cheap to adjust the tension and compression independently. It is also possible to perform the solenoid valve as a proportional valve, thereby making it possible to specify the biasing force regardless of the opening path of the throttle with the current exactly. The range I is influenced by the bypass 17 "'while the range Il is controlled by the comfort valve 15. The range of the build-up attenuation III in a frequency range of 1 to 1.5 Hz is varied by the variable build-up valve 17 while the axle damping of the range IV is effective in the frequency range 10 to 40 Hz, and the design damping and axle damping can thus be adjusted and varied independently of each other.

FIG. 9 shows a schematic suggestion of the embodiment of a helical spring throttle, likewise effective with two overflow channels 6, 7 in the direction of tension and compression, in which valve plates 26, 27 are held in valve seats by means of helical springs 36, 37.

Figure 10 shows a plan view of a throttle module with a total of four valves, of which two as blow-off valves 16 'with a diameter of more than 20mm as Achsventile and two other valves 16 with diameters between 10 and 15 mm as working valves for the body damping are formed. In addition, a solenoid valve 18 is provided for the tension and compression, with the adjustment of the spring force characteristic can be done very easily. The working valves 16 are located in Zugrich- tion a smaller opening diameter than in the pressure direction, the same applies to the blow-off valves 16 '. It is possible to combine the working valves 16 and the blow-off valves 16 'in a valve, wherein the opening pressure for train is in the range of 3 to 5 bar, for the pressure stage in the range of 1, 5 - 2.5 bar , For tension and compression bypasses are provided with different flow cross-sections, which are preferably arranged in the working valves 16. By adjusting the damper characteristic, the gas spring damper unit can be adapted to changing vehicle parameters and driving situations, for example, it can be responded to the weight, cornering and braking and deceleration processes. It is also possible to adjust the suspension according to the wishes of the driver, for example as a sports or comfort suspension. In addition to these adaptive concepts, it is also possible to react to road changes, wheel vibrations and the like, in which the damper characteristic curve is adjusted accordingly.

The advantage of a helical spring choke is a relatively low actuating force, since the ratio of used cross-sectional area to the shelf area in the case of a helical spring choke is approximately 1.

Claims

claims

1. Gas spring Dämpfθr unit (1) in vehicles with at least one displaceably mounted displacement piston (2) and two Verdrän- gerkammern (3, 4) whose volume increases or decreases depending on the direction of displacement of the displacement piston (2) and the overflow (6, 7), in which throttle valves (16, 16 ', 16 ", 17, 17', 17", 17 '") are arranged, are interconnected, characterized in that a plurality of throttle valves (16, 16', 16 ", 17, 17 ', 17", 17' ") of different valve characteristics in one

Direction of flow are effectively arranged and a throttle valve (17) for a damping of natural frequencies in the range of 1 to 1.5 Hz and another throttle valve (17 ') is designed for damping natural frequencies in the range of 10 to 40 Hz.

2. Gas spring damper unit according to claim 1, characterized in that the throttle valves (16, 16 ', 16 ", 17, 17', 17"), which are effective in a flow direction, open at different flow pressures.

3. Gas spring damper unit according to claim 1 or 2, characterized in that the throttle valves (16, 16 ', 16 ", 17, 17', 17") for the tension and compression stage have different flow cross-sections.

4. Gas spring damper unit according to claim 3, characterized in that the throttle valves (16, 16 ', 16 ") for the pressure stage have a larger flow cross-section than the throttle valves (17, 17", 17 ") for the rebound.

5. Gas spring damper unit according to one of the preceding claims, characterized in that the throttle valves (16, 16 ', 16 ", 17, 17', 17") resiliently mounted against the flow pressure are open and only after reaching a certain flow pressure.

6. Gas spring damper unit according to claim 5, characterized in that the effective in a flow direction throttle valves (16, 16 ', 16 ", 17, 17', 17") have a different bias.

7. Gas spring damper unit according to one of the preceding claims, characterized in that the throttle valves (16, 16 ',

16 ", 17, 17 ', 17") are pressed into the valve seats via coil springs (36, 37).

8. Gas spring damper unit according to one of the preceding claims, characterized in that the throttle valves (16, 16 ',

16 ", 17, 17 ', 17"), which are effective in one direction of flow, have different flow cross-sections.

9. gas spring damper unit according to one of the preceding Ansprü-, characterized in that the displacement piston (2) double-acting formed in a cylinder (20) is mounted.

10. Gas spring damper unit according to claim 9, characterized in that the throttle valves (16, 16 ', 16 ", 17, 17', 17", 17 '") are mounted in the displacer piston (2).

11. Gas spring damper unit according to one of the preceding claims, characterized in that between the displacement chambers (3, 4) at least one throttle valve (17 '") is formed as a bypass.

12. Gas spring damper unit according to claim 11, characterized in that the bypass (17 '") in a throttle valve (16, 16', 16", 17, 17 ', 17 ") is formed.

13. Gas spring damper unit according to claim 11 or 12, characterized in that per flow direction, a bypass (17 '") is formed and the bypass (17'") in a flow direction NEN larger flow cross-section than the bypass (17 '") in the other flow direction.

14. Gas spring damper unit according to one of the preceding claims, characterized in that an adjusting device for adjusting the valve characteristic, in particular the bias of at least one throttle valve (16, 16 ', 16 ", 17, 17', 17") is provided.

15. Gas spring damper unit according to claim 14, characterized in that the adjusting device is an electromechanical

Actuator has.

16. Gas spring damper unit according to claim 14 or 15, characterized in that a valve spring for the throttle valve (16, 16 ', 16 ", 17, 17', 17") is provided, which is assigned a foreign-powered actuating mechanism, over which the spring preload is variable.

17. Gas spring damper unit according to claim 16, characterized in that the adjusting mechanism as a screw or

Adjusting nut is formed.

18. Gas spring damper unit according to claim 1, characterized in that at least three throttle valves (16, 16 ', 16 ", 17, 17', 17") are provided per flow direction.

19. Gas spring damper unit according to claim 1, characterized in that at least four throttle valves (16, 16 ', 16 ", 17, 17', 17", 17 '") are provided for each flow direction, one of which a bypass valve (17 '"), a throttle valve (17) operating a frequency range of 1 Hz to 1.5 Hz, a throttle valve (17') operating a frequency range of 10 Hz to 40 Hz and a comfort valve (17") as pilot operated Bore is present.

20. Gas spring damper unit according to claim 1, characterized in that the throttle valve (17) for the frequency range from 1 Hz to 1, 5 Hz and / or the throttle valve (17 ') for the frequency range of 10 Hz to 40 Hz Having adjusting mechanism.